What can we learn about evolution from fossils?

Fossils are the preserved remains or traces of animals, plants, and other organisms from the past ... Paleontologists can determine the age of fossils using methods like radiometric dating and categorize them to determine the evolutionary relationships between organisms.

We can learn what some of now a days species are possibly related to species a long time ago.

Fossils can also try to see how far back we can go back into time